At 10:57 AM 10/30/2006, Robert G. Brown wrote:
>On Mon, 30 Oct 2006, Geoff Jacobs wrote:
>>>>>Mmm... Except... The high res images are from a plane because you can't
>>>>>really make out the fine details from a satellite through the earth's
>>>>>atmosphere.
>>>>>>It's true that most of the Google Earth images are aerial photos, but
>>>I would imagine that one can get 10s of centimeter resolution from orbit
>>>on Earth (assuming that clouds aren't in the way). An old surveillance
>>>satellite (Corona) was doing better than 2 meter resolution in the 1970s.
>>>>Absolutely. Assume modern recon sats use a primary mirror similar in
>>size to the Hubble primary (both made by Perkin-Elmer). Calculating the
>>Rayleigh limit for an Improved Crystal satellite such as that launched
>>with USA 186 (Apogee 1050km, Perogee 264km) gives a max resolution of
>>7.9cm at 600nm and min resolution 31.5cm at 600nm. Space Imaging
>>typically quotes max res. of 1m with IKONOS. DigitalGlobe says 61cm in
>>B&W with their satellites.
>>>>I would suspect that methods for dealing with atmospheric degradation is
>>the secret sauce in the NROs architecture, especially WRT real-time
>>applications of IMGINT.
With a nice braadband pipe back to the ground, and a modest rack of
computers, amazing things are possible, including resolving things
below the diffraction limit. Look at the stuff people have been
doing with imaging ISS and Shuttle from the ground with fairly small
telescopes. Indeed, the variable atmosphere can actually help,
because it essentially gives you the ability to do multiple samples
with statistically independent distortions, so you can "average" them
to reduce the variance. Something else to do with that Beowulf
sitting in your garage..
I seem to recall that the ambitious amateur can get resolutions less
than a meter with "available at retail stores" kind of optical equipment.
There is a ground based optical observing site on Mt. Haleakala to do
just this sort of thing (or, at least, it's rumored to do so).
>Awww, what you guys are all trying to tell me seems to be that I
>shouldn't believe everything I see on 24. So agent Jack Bower really
>can't call back to CTU to track the driver of the grey mercedes from
>where he abandons the car to where he disappears into the abandoned
>military bomb shelter -- at night and independent of the LA weather and
>smog.
IR imagery is one thing to think about. Radar is another. X band
radar (9-10 GHz) easily gives you 3cm sorts of resolution, especially
with SAR processing.
>You're really shaking my worldview here. Next you're going to tell me
>that Gil Grissom can't really prove that the sultry blonde did it from
>the tiny splinter removed from the carpet at the feet of the victim that
>could only have come from her imported chopsticks being hurled at high
>velocity through the victim's brain...;-) Or that they can take the
>blurred, crappy, low resolution picture from the surveillance videocam
>in the parking deck, load it into their CSI Windows GUI and click on it
>to prove that the perp was wearing argyle socks and had a mole on his
>left butt-cheek by mysteriously increasing the available pixel
>resolution by 2000% or so.
>>I'll bet that MICROSOFT's CSI/beowulf software can do that and match
>fingerprints too...:-)
But of course. You have the name wrong, though. That's MS Vista
Crime Scene Investigation/Clustering Edition, and the surveillance
camera imagery will need to be processed through an appropriate
Digital Rights Management system to make sure that you have properly
licensed the right to superresolution processing, no?
Jim